The background of the invention will be set forth in two parts.
1. Field of the Invention
The invention relates to microwave resonators and more particularly to thermal compensation for frequency control of microwave resonators.
2. Description of the Prior Art
Generally speaking, regardless of the material used, the frequency of a tuned cavity or resonator will change as a function of temperature. As the temperature rises, the material expands, the cavity volume and characteristic length increase and consequently the frequency of the cavity decreases. Of course, the converse is true for decreasing temperature.
The conventional technique to temperature compensate microwave cavities has been to utilize differential temperature coefficients between the tuning screw and its carrier. This provides a very limited amount of temperature compensation and, as will be shown subsequently, the total movement available by using the prior art coaxial technique is orders of magnitude less than the temperature compensating movement of a frequency governing structure of the present invention.